Conformal coating vs. potting is a common comparison in PCB protection. Each option has benefits and drawbacks, making proper selection crucial, usually based on the application’s needs. Here, we will help you determine the method to use.
What is Conformal Coating in PCB?
A conformal coating in PCB manufacturing is a thin layer of protective material applied to the board’s surface. The material is usually a polymer meant to shield the board from environmental damage.
Some polymers perform better than others. Their selection, therefore, depends on the desired protection level and other qualities, such as durability and cost.
The coating introduces minimal thickness and weight to the PCB. It’s also flexible and conforms to the board’s geometry. These attributes make it suitable for portable devices and applications where space is at a premium.
What is PCB Potting?
Potting refers to a process that encloses the entire PCB assembly in a thick layer of epoxy, silicone, or another resin. It requires a custom housing to hold the resin, which then cures to form a solid mass around the board.
The type of resin determines the protection benefits of potting. For instance, the flexibility of silicone makes it excellent for vibration damping.
Conditions that can benefit from the technique are those that experience excessive vibrations, impact forces, and extreme temperatures. It’s also an excellent option for water immersion and IP theft protection.
Resource: https://forum.arduino.cc
Conformal Coating vs. Potting
While both are PCB protection methods, they differ in many ways, from protection levels to best applications. Below is their side-by-side comparison to shed more light.
Material Options
Conformal films are thin, flexible polymers. They include epoxy, polyurethane, silicone, parylene, and acrylic. Each polymer has unique properties that determine its usability benefits.
Potting compounds are also resins. Examples include epoxy, polyurethane, and silicone. They are thicker than coating materials and meant to set into a rigid mass around the PCB, providing maximum protection.
Application Difference
You apply a conformal film by spraying, brushing, vapor deposition, or dipping the PCB in a resin bath. The procedure is manual or automated.
The resin cures in minutes or hours, depending on its type and the curing method. Curing methods include applying heat, UV light, and using moisture.
Potting involves pouring liquid resin into a custom housing that contains the PCB or a dammed area. Like coating, the application is either manual or automated, depending on the production volume.
Curing also takes longer than the setting of conformal films. It may require UV light or heat, depending on the polymer type and other factors.
Weight and Thickness
Conformal films weigh less. They do not increase a device’s mass and are suitable for portable, compact devices. The layers are also thin, averaging 25-250 microns.
Potting produces a thick layer measuring 1-10 mm, providing greater mechanical strength. However, that makes it more bulky, increasing the board’s weight and that of the end-use electronic devices.
Levels of Protection
Conformal coatings offer moderate protection. The film generally shields the board against mild environmental factors, including moisture, dust, or other contaminants.
Potting provides better protection against the elements and other causes of damage, such as heat, impact, and vibrations. It also makes the board tamperproof for IP theft protection.
While coatings are too thin to impact thermals, thermally conductive potting compounds can help dissipate heat away from high-power components to the outer enclosure.
Additionally, a potted circuit board has better insulation and can withstand environmental conditions where arcing is a concern. Examples include power electronics and other high-voltage uses.
Ease of Rework
Coating makes inspecting and reworking PCBs easier because it’s only a few hundred microns thick. This property makes it an ideal choice when the final product is likely to undergo repair.
Potted PCBs are harder to repair. The potting compound covers the entire surface and components in a thick mass, making its safe removal difficult. Potting suits disposable modules or boards that are replaceable rather than repairable.
Cost implications
Coating uses less material and other resources, such as time and tooling. Therefore, it is a more cost-effective method that suits many applications.
Potting uses more resin. It also takes longer to set and requires custom enclosures, which adds to the overall cost.
Resource: https://www.youtube.com/watch?v=GfqsqPBqoYE
Application Difference Between Conformal Coating and Potting
The characteristics of each protection method determine its suitability for specific applications. Here is an overview of when to apply a thin film and when to prefer potting.
When to Use Conformal Coating
The film is a cost-effective option for milder application conditions. It generally suits the moderate protection needs. The following are key benefits of conformal coating.
- Cost-effective protection for general-purpose or consumer electronics.
- Negligible weight and thickness for lightweight and miniaturized products.
- Easy removal for circuit boards that may require repair or rework.
When to Use Potting
Potting provides heavy-duty protection for severe conditions and high-reliability PCBs. Key applications include industrial electronics, automotive, defense, and aerospace. Its usage advantages include:
- Excellent durability for long-term protection needs.
- Excellent waterproofing for underwater applications.
- Improved insulation that prevents arcing or short circuits in high-voltage applications, such as power electronics.
- Tamperproof encapsulation for applications that require protection against intellectual property (IP) theft.
How to Choose Between Conformal Coating vs. Potting
Most often, PCB designers have to choose between potting and coating for environmental and other protection. Consider these factors when deciding which technique to use.
- Desired protection needs (environmental, mechanical, thermal, and electrical)
- End-use product size and weight (potting can make a printed circuit board bulky)
- Reworkability and future repair needs (coating allows it without causing damage)
- Cost projections and production volumes (coating is cheaper for higher volumes)
Your selection has a significant impact on the PCB’s price and reliability. Choose potting for demanding applications and conformal film for those with moderate requirements.
Conclusion
Conformal coating and potting protect circuit boards in different ways—one through a precision thin film and the other through total resin encapsulation. Choosing the right method ensures your electronics survive their specific operating environment while meeting repair and weight requirements.
Secure your electronics against the elements. Consult with Venture’s protection specialists to determine the most reliable encapsulation or coating strategy for your ruggedized application.
